Hard alloy



1o tivel has become Patented Mar. 1, 1932 EE D STATES PATENT OFFICE- :1 i, PR INZ 2U LilWENS'IEIN AND WILHELM MU'LLER, OI BERLIN, GERMANY; OLGA.

PBINZESSIN ZUR LIPPE, EXECUTRIX OF SAID KARL PRINZ zv LilWENSTEIN, IDE- OEASED; ASSIGNOBS TO HIRSCH, KUPFER' UND MESSINGWEBKE AKTIENGESELL- SCHAFT, 0F FINOW (MARK), GERMANY HARD ALLOY Ho Drawing. Application filed December 11, 1828, Serial No 825,404, and in Germany February 11, 1928.

5 alloys represent,- therefore, an excellent starting material for tools and working implements of all kinds especially drawing stones. But the resistance of these har metals to chemical influences is comparaslight, which renders them unsuited for t e working of such materials that when being clamped in for bein worked affect the tool chemically, es ecia y if the tem eraturearisin during t e working proce ure Ei h by reason of the hlgh working speed. aterials acting in this way are hard rubber, vulcanized fibre, lazed cardboard, pertinax, certain sorts 0 paper, and

similar materials having or anic -components. To give an example a o for an morganic substance we mention the anhydrous sulphate of calcium (CaSO which, as it seems, impairs the cutting capacity of the drilling and cutting tools by its radical.

Now the present inventlon relates to an iron alloy which, on the one hand is, as regards hardness, not inferior to the abovementioned hard alloys owing to its contents in heavy metals in connection with carbon,

0 and which, on the other hand, represents a chemically nearly unafiectable tool substance for the working of materials of the above- I stated kinds by reason of an addition of chromium and cobalt, the amount of which depends upon, and stands in a certain relation to, the amount of the heavy metal.

A proportion. which is characteristic for V the present invention and is, probably the cause of its chemical stableness is this: tungb sten:chromium:cobalt=about 8:2:1 (per 5 numbers of the pro rtion stated should,"

preferably, not excee 10%.

cent by weight).

Anyhow, the amount of iron shouldnot surpass 55 per cent by weight of the total amount of the alloy. Deviations of the Accordm to the desired hardness and to the admissi le brittleness the proportion of the com onents tungsten, chromium and cobalt with respect to the amount of the iron,

latter metal u as well as to the amount of the carbon, (this latter being kept between 1 and 4 per cent) varies. A typ1cal analysis of a tough material of medium hardness is, for instance:

55 per cent of iron,

32 per cent of tungsten,

8 per cent of chromium,

4 per cent of cobalt,

1 per cent of carbon.

In contradistinction to this composition a very hard material which is sufiicientl tough to be used for the manufacture of ce lulose threads is composed as follows:

10 per cent of iron,

per cent of tungsten,

16 per cent of chromium,

7 per cent of cobalt,

2 per cent of carbon.

It is known that in many hard alloys molybdenum can be substituted for the tungsten either totally or to a very large proportion.

With alloys according to the present invention such substitution is possible only in a certain measure, viz. at the highest up to 25% of the contents of tungsten; the most favorable percentage in relation to the tungsten is about 12.

For the purpose of increasing the chemical stableness nickel which is, as is kindred to cobalt can be substituted for this thereof. But in this respect attention must be paid to thepoint that in the majority of cases the toughness of the alloy is diminished by said substitution, but its hardness is not increased.

Substituting for the iron another metal which is kindred to it has up to now not proved favorablfeaf This fact is not disproved by the other fact that a small addition of manganese improves the texture of the alloy. Probably manganese acts in this instance merely as a reducing agent.

In order to increase the hardness still more, one or more other known hardening substances, viz. silicium, boron, zirconium, titanium, nitrogen, vanadium, beryllium, cerium, and so on, can be added to the alloy, but the per cent thereof should, at the highest,

known,

to one half of the amount.

ion

be 4 per cent, as otherwise the alloy becomes too brittle. The hard metal alloy described is particularly suitable for the production of ro- 6 jectiles for rifles and other fire-arms, an for the manufacture of projectile casin s (shells) also for the points of pro'ectiles o large and small calibersas well as or mines, torpedoes and the like.

10 We claim:

1. A hard alloy having a high mechanical strength and chemical stable'ness, suitable for tools and working implements, consisting of from-10 to 33 per cent of iron, 1 to 4 percent of carbon, 64 to 46 percent of tungsten, 16 to 11.5 per cent of chromium and 8 to 5.5 per. cent of cobalt, said three last named substances having among themselves the proportions of 8 :2: 1, all by weight.

20 2. A hard alloy having a high mechanical strength and chemical stableness, suitable for tools and working implements, consisting of from 10 to 33 per cent of iron, 1 to 4 per cent of carbon, 48 to 35 per cent of tungsten, 16

to 11 per cent of molybdenum, 16 to 15.5 per cent of chromium and 8 to 5.5 per cent of cobalt, the ratio of thetotal percentage of tungsten and molybdenum to that of chromium and that of cobalt being 8 :2: 1.

3. A hard alloy having a high mechanical strength and chemical stableness, suitable for tools and working implements consisting of from 10 to 33 per cent of iron, 1 to-4 per cent of carbon, 64 to 46 per cent of tungsten, 16

to 11.5 per cent of chromium, 4 to 3 per cent of cobalt and 4 to 3 per cent of nickel, the

ratio of the total percentage of tungsten to that of chromium and that of cobalt and nickel being 8:2:1.

4o 4. A hardalloy having a high mechanical strength and chemical stableness, suitable for tools and working implements consisting of 10 to 33 per cent of iron, 1 to 4 per cent of carbon, 48 to 35 per cent of tungsten, 16 to 11 per cent of molybdenum, 16 to 5.5 per cent of chromium, 4 to 3 percent of cobalt and 4 to 3 per cent of nickel, the ratio of the total percentage of tungsten and molybdenum to that of chromium and to that of cobalt and 50 nickel being 8:2: 1. i

In testimony whereof we aflix our'signatures.

KARL PRINZ zU LOW NSTEIN. WILHELM MULLER. 

